The Contractor shall participate with other selected investiators in the development and implementation of a standard protocol according to the manual of operations for a double blind study to determine whether or not the regular administration of aspirin to people who have had a documented myocardial infarction will result in a significant reduction in total mortality over a three year period of follow-up. Study phases, within the five year period, will be established in the initial planning sessions and all centers will adhere to this schedule. Year I involves the planning and preparation of the forms to be used; the planning for patient recruitment, completion of the protocol and manual of operations; and the beginning of patient recruitment.